Consider the sequence $\{a_n\}$ such that $a_n = \prod_{k=1}^n P_k +1$ where $P_k$ is kth prime. How can I prove exist composite number in this sequence without by examples like $2\times3\times5\times7\times11\times13 +1=59\times 509$?
2026-03-26 21:27:06.1774560426
Prove the form $P_1P_2\cdots P_n + 1$ where $P_k$ is kth prime is not necessary a prime.
68 Views Asked by user369184 https://math.techqa.club/user/user369184/detail AtRelated Questions in ELEMENTARY-NUMBER-THEORY
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